Our long range goal is to be able to effectively use biochemical assays to predict prognosis and clinical cause of human breast cancer patients with resectable cancers as well as in patients with recurrent or metastatic disease. These studies are intended to identify biochemical parameters that would provide information concerning the nature and usefulness of endocrine therapy. Specifically, we are studying the estrogen receptor protein, progesterone receptor protein and steroid sulfotransferase activities of human breast cancer tissues from a patient population from MCV hospitals as well as community hospitals. We hope to be able to establish biochemical correlates between the results from the estrogen and progesterone receptor assays and the steroid sulfotransferase and the clinical course in these patients following therapy.